Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: available modems
Message-ID: <3925.28162bac@hayes.uucp>
Date: 25 Apr 91 01:06:52 GMT
References: <1744@marlin.NOSC.MIL>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 47

In article <1744@marlin.NOSC.MIL>, bryan@marlin.NOSC.MIL (Dale
Bryan) writes: 

> i'm looking for info on board level modems that are currently
> on the market that have the following features:
> 
> 	full duplex and half duplex operation
> 	v.22,v.26,v.27,v.29,v.33 compatibility
> 	fallback from v.33 to all the above standards
> 	adaptive echo cancellation and equalization
> 	adaptive carrier deviation correction
> 	small package size

This is a strange request -- because, of the five modulations you've 
listed, four are _leased line only_; only V.22 is for dial-up.  V.26 
_bis_ and V.26 _ter_ are dial-up modems, but not V.26.  V.27ter is 
dialup, but not V.27 or V.27bis.  V.29 is not dial-up, although some 
companies have produced proprietary half-duplex versions of V.29 for 
dial-up applications.  V.33 is definitely not suitable for dial-up, 
because the turnaround time in a half-duplex mode would be on the 
ourder of 1.4 seconds.  I know of NO modem that implements all of 
the modulations you're looking for -- in fact, I don't know of any 
that even support two of them.  You rarely see modems intended for 
leased-line use combined into a single box (and definitely not with 
automatic fallback!)

Can you explain your requirements a bit more?  Why do you need these 
specific modulation schemes -- all in one modem?

> also, does anyone know of another multicarrier type modem besides
> Telebit modems.

The only other company I'm aware of that sells multicarrier modems 
for dial-up applications is Forval America in Midvale, Utah.  Uh, on 
second thought, I think they've announced it, but that they're not 
shipping yet.  Their design is for a multicarrier modem with echo 
cancellation (full duplex!), but I think they've been delaying 
introduction to see how the CCITT V.fast work progresses.  I believe 
Ven-Tel also sells multicarrier modems, bbut they're licensed from 
(and probably built by) Telebit; Anderson-Jacobsen and DCA also 
(used to) sell repackaged Telebit Trailblazers.

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net